Supplementary fuel mixture for cold starting diesel engines



United States Patent O SUPPLEMENTARY FUEL MIXTURE FOR COLD STARTING DIESEL ENGINES No Drawing. Application December 7, 1953 Serial No. 396,786

4 Claims. (CI. 44-53) This invention relates to a supplementary fuel mixture for cold starting diesel engines. More particularly, this invention discloses an improved supplementary fuel mixture for initiating combustion in diesel engines at subfreezing temperatures.

In recent years, the problem of starting diesel engines at sub-freezing temperatures has been accentuated by the establishment of arctic military bases vital to the national defense.

In general, two procedures have been advanced to solve the problem of cold starting of diesel engines. One procedure has involved the use of a special starting-up fuel comprising a diesel oil fraction plus van'ous aliphatic ethers such as diethyl ether, diethyl Carbitol and diethyl Cellosolve. A major drawback of this type procedure has been the necessity of supplying a special fuel tank and means for introducing the special fuel into the combustion chamber of the diesel engine. The other approach to the problem of cold starting has involved the manifold injection of dialiphatic ethers, for example, diethyl ether, in combination with the injection of regular diesel fuel into the combustion zone. Manifold injection of diethyl ether in combination with the use of a regular diesel fuel has the serious drawback that severe combustion shock is encountered and engine wear is noticeably increased. The supplementary fuel mixture of this invention effects cold starting of diesel engines in a much shorter period of time than has been possible with previous fuels and, in addition, is satisfactory from the standpoint of combustion shock and engine wear.

This invention is a continuation-in-part of our copending application Serial No. 377,239, filed August 28, 1953, now U. S. Patent No. 2,774,656, which discloses supplementary fuel mixtures for cold starting diesel engines by manifold injection of a mixture comprising 2 to 50 percent dialiphatic ether and 50 to 98 percent dialiphatic glycol ether. In the instant invention, cold starting of diesel engines is effected by manifold injection of a mixture comprising a 1,1-dialkoxy alkane and an ether.

In accordance withthe invention, diesel engines are started at sub-freezing temperatures by using regular diesel fuel in the main injector, while a mixture of 1,1-dialkoxy alkane and an ether selected from the group consisting of dialiphatic ethers, dialiphatic glycol ethers and mixtures thereof is introduced into the air manifold, The 1,1-dialkoxy alkane component which may also be called an acetal comprises to 90 percent of the total mixture and has the general formula on R"OH wherein R and R are aliphatic hydrocarbon radicals 2,842,432 Patented July 8, 1958 formula ROR or a dialiphatic glycol ether of the general formula RO(CH CH O),,R or mixtures thereof. In both of these formulae, R and R also represent aliphatic radicals containing 1 to 4 carbon atoms; n is an integer having a value of l to 4. Preferred fuels for use in the process of the invention are the following mixtures: diethoxy methane-diethyl ether; diethoxy methane-diethyl Cellosolve; diethoxy methane-diethyl Carbitol. Diethyl Cellosolve and diethyl Carbitol are commercial products manufactured and sold by Carbide and Carbon Chemicals Corporation, and identified on page 5 of their booklet entitled, Ethers and Oxides, copyright 1945, as ethylene glycol diethyl ether and diethylene glycol diethyl ether, respectively.

A particularly advantageous feature of this invention is that the manifold introduction of the mixture of ether and dialiphatic glycol ether does not require special apparatus. A Bosch injector specifically designed for spraying fuels into the intake manifold has been used with excellent results, but even better performance has been realized by injecting the special fuel into the intake manifold manually with a pump-type oil can, a Flit gun or an aerosol bomb. The excellent results obtained with manual injection using an oil can or Flit gun prove that the cold starting fuel mixture of the invention is independent of the state of sub-division of the introduced fuel and is a direct function of its composition.

The fact that the invention appears to be independent of the mode of introduction into the manifold eliminates the necessity of installing an extra fuel tank and a spray injector in order to practice the invention. Manual intro duction of the acetal-ether blend by means of a pumptype oil can, a Flit gun or a Kelite gun is simply practiced without the need for installing extra equipment on each engine.

An outstanding advantage of cold starting diesel engines by manifold introduction of an acetal-ether blend is its freedom from combustion shock and excess engine wear. The blend is entirely satisfactory from the standpoint of both lubrication and corrosion. Even after many cold starting runs with manifold introduction of an acetal-ether blend, an overhauled engine shows negligible wear and.

wherein R and R are aliphatic groups which may be either alkyl or alkenyl groups containing up to 4 carbon atoms and R" is hydrogen or an aliphatic hydrocarbon group containing up to 4 carbon atoms; the R and R may be identical or different alkyl or alkenyl groups. Examples of acetals which can be used in the process of the invention arediethoxy methane, 1,1-diethoxy ethane, n-dibutoxy methane, 1,1-dimethoxy butane and di-2-n-butenoxy methane. Diethoxy methane is preferred for use in the manifold injected mixture because of its availability and because optimum results are obtained therewith.

In the general formula ROR for the dialiphatic ether component of the manifold introduced mixture, Rand R represent the same groups as in the general formula for the acetal component of the introduced mixture.

3: Examples of aliphatic ethers which can be used in the process of the invention are diethyl ether, dimethyl ether, di-isobutyl ether, methyl n-propyl ether and ethyl isopropyl ether. Diethyl ether is a preferred dialiphatic ether.

In the general formula RO(CH CH O),,R' for the dialiphatic glycol ether, n is 1 to 4, and R and R represent the same radicals as in the acetal general formula, that is, they are alkyl or alkenyl groups having 1 to 4 The above data clearly demonstrate the eifectiveness of the supplementary fuel mixtures of the invention for cold starting diesel engines. Run 1 shows that a diesel engine cannot be started using a standard diesel fuel at -30 F. Runs 2 and 3 show the results obtained with the use of special cold starting fuels comprising a mixture of dialiphatic glycol ethers and hydrocarbon fractions; it is noteworthy that average starting times of over 2 /2 minutes were required. Runs 4 to 6 illustrate the carbon atom Glycol ethers from whi h the anifold 18 use of manifold introduction of individual ethers in introduced mixture is prepared are exemplified by diconjunction with the use of regular diesel fuels in cold ethyl Cellosolve, C H OC H OC H diethyl Carbitol, starting; the best results were obtained by manifold C H OC H OC H OC H di isopropyl Cell l introduction of diethyl Cellosolve with which cold start- C H OC H OC H ethyl propenyl c bit l, ing was effected in 0.9 minute; with manifold introduction of diethyl ether and diethyl Carbitol separately, C2H5OC2H4OC2H4OC3H5 average starting times of 1.67 and 2.2 minutes, respecdi-n-butyl Cellosolve, C H OC H OC H and diethyl tively, were required. Run 7 shows cold starting emtetraglycol, C H O(C H O) C H Diethyl Carbitol and ploying manifold injection of diethoxy methane. Runs diethyl Cellosolve are the preferred glycol ethers for 8 to 12 illustrate cold starting with the supplementary formulating mixtures used in this invention. fuel mixtures of this invention.

The composition of the acetal-ether blend is within it is noteworthy that the average starting times obthe limits of 10 to 90 percent acetal and 90 to 10 percent tained using mixtures of an acetal and an ether are ether. With diethoxy methane-diethyl ether, diethoxy substantially shorter than any of the runs using known methane-diethyl Cellosolve, and diethoxy methane-diethyl starting fuels. The synergistic action of the acetal-ether Carbitol mixtures, optimum results are obtained with a and acetal-glycol ether blends is clearly demonstrated in mixture containing between about 50 and 80 percent this table since the average starting times obtained with acetal and 20 to 50 percent ether. Although the prethe blends are much shorter than either of the components ferred composition varies with the particular acetal and separately. It is also noteworthy that excellent results ether components of the introduced fuel mixture, in are obtained regardless of the mode of injection of the general it can be stated that best results are obtained acetal-ether and acetal-glycol ether blends. The absowith mixtures wherein the acetal component constitutes lute independence of the invention from equipment limithe major portion of the mixture. tations is unusual and proves that it is not dependent The process of the invention for cold starting diesel on the fineness of the spray of manifold injected fuel. engines was evaluated in a single clyinder Fairbanks- Obviously, many modifications and variations of the Morse diesel engine model -B, which was installed invention, as hereinbefore set forth, may be made within a cold room maintained at -25 F. and below. As out departing from the spirit and scope thereof, and, a diesel fuel, there was used a Texas Company product therefore, only such limitations should be imposed as sold as Crystalite having an IBP-minimum of 325 F. are indicated in the appended claims. and an EP-maximum of 525 F. Manifold introduction 40 We claim: of the acetal-ether mixture was effected manually with 1. A supplementary fuel mixture designed for cold an OCS-snap-on-pump oiler, a Flit gun and a Kelite starting diesel engines by manifold introduction congun V sisting essentially of from 20 to 80 percent by volume The effectiveness of the supplementary fuel mixtures of diethoxy methane and from 80 to 20 percent by of the invention in cold starting diesel engines was devolume of a compound selected from the group contermined in terms of the average starting time in minutes sisting of diethyl ether, ethylene glycol diethyl ether, required to initiate operation of the test Fairbanks-Morse diethylene glycol diethyl ether, and mixtures thereof. engine. In the following table, there are shown results 2. A supp ementary fuel according to claim 1 conobtained when cold starting a Fairbanks-Morse engine sisting essentially of to percent diethoxy methane at 25 F. and below by manifold injection of acetaland 50 to 20 percent diethyl ether. ether mixtures in comparison with manifold injection 3. A supplementary fuel according to claim 1 conof ether, dialiphatic glycol ether and acetal separately sisting essentially of 50 to 80 percent diethoxy methane and with the use of various cold starting fuel blends. and 50 to 20 percent ethylene glycol diethyl ether.

Tem- Average Fuel Manifold Introduced Fuel Means of Manifold perature, Starting Introduction F. Time,

Min.

1 Orystalite None 30 No start; 2 50- 0 Diethyl Oarbitolo 30 2.48

Orystalite. 3 50-50 Diethyl Oarbitoldo 30 2.33

Stoddard Solvent. 4. Orystalite Diethyl Carbitol. ---30 2. 20 5 do.... Diethyl Cellosolve 30 0.90 6. do Diethyl Ether "do"... 30 l 1. 67 7 d0 Diethoxy Methane ModifiedKelite 30 1.301 s -410 50% Diethyl Cellosolve in with]. -30 0.581 Dlethoxy Methane. 50% Diethyl Carbitol in do -30 0.595

Diethoxy Methane. 20% Diethyl Ether in Pump oiler 30 0.380

Diethoxy Methane. 11 do 20% Diethoxy Methane in do 30 0.762

Diethyl Carbitol. 33 Diethyl Oarbitol. 12 do {33%7 Diethyl Cellosolve }Fht; gun -31 0. 736

33%% Diethoxy Methan 1 Value average of individual readings of from 0.55 min. to 3.31 min.

4. A supplementary fuel according to claim 1 consisting essentially of 50 to 80 percent diethoxy methane and 50 to 20 percent diethylene glycol diethyl ether.

References Cited in the file of this patent UNITED STATES PATENTS Nikaido Apr. 27, 1926 Lipkin Nov. 19, 1940 Greathouse Dec. 5, 1944 Goodale Nov. 25, 1947 Moody July 25, 1950 OTHER REFERENCES Handbook of Chemistry and Physics, 16th edition, 10 Chemical Rubber Publishing Co., Cleveland, Ohio, 1931,

page 310. 

1. A SUPPLEMENTARY FUEL MIXTURE DESIGNED FOR COLD STARISNG DIESEL ENGINES BY MANIFOLD INTRODUCTION CONSISTING ESSENTIALLY OF FROM 20 TO 80 PERCENT BY VOLUME OF DIETHOXYS METHANE AND FROM 80 TO 20 PERCENT BY VOLUME OF A COMPOUND SELECTED FROM THE GROUP CONSISTING OF DIETHYL ETHER, ETHYLENE GLYCOL DIETHYL ETHER, DIETHYLENE GLYCOL DIETHYL ETHER, AND MIXTURES THEREOF. 